Production Technology of Amaranthus (Amaranthus sp.)
Rohini,N.,1* , N. Pandiarana2
Amaranthus (चौलाई) is a primarily used as a pot herb. It is a most common leafy vegetable grown during summer and rainy season in India. The fresh tender leaves and stem give delicious preparation on cooking. It belongs to the family Amarantaceae. Most of the amaranthus species are originated in India or Indo-China region. Other species have originated in various other centres, such as North America, Central America, Mexico, South America and Mediterranean region. Among the leafy types A.tricolour L. is the main cultivated species in India. Other cultivated species are A. blitum and A. tristis it is more popular in south India.
Climate and Soil
Amaranthus is a warm season crop adapted to the conditions of hot, humid tropics. However, it can also be grown under temperate climate during summer. It belongs to C-4 group of plants and has efficient photosynthetic abilities and responds best to full sunlight,
Amaranthus grows in every type of soil but the best crop is harvested from fertile loamy soils. The proper drainage system in the field is necessary as the crop is susceptible to water logging. The best soil pH range is between 5.5 and 7.5 but some of the strains are successfully grown in soils with the pH up to 10. The soil should be brought to a fine tilth by ploughing 3-4 times followed by planking.
Following varieties are recommended for cultivation in India,
Badi Chauli: This variety has been released by the IARI, New Delhi. It is highly suitable for commercial cultivation. It has a thick tender stem and large leaves. It is best suited for summer season and when sown in early summer, it continues to give cuttings up to tile end of the rainy season.
Chhoti Chauli: This variety has also been released by the IARI and is a quick growing variety with slight dwarf erect plants. The stem is thinner and the leaves are smaller than those of Badi Chauli. It is best suited as an early summer crop and is suitable only for kitchen and container gardening.
CO-I (A. dubius): This variety has been released by the Agricultural College, Coimbatore. It is suitable for growing for tender greens and immature stems which are thick and fleshy. The leaves are broad, thick and dark green in colour and grows vigorously and produces very high yield.
CO-2 (A. tricolor): The plants are erect with moderate branching. Its leaves are long, green and lanceolate. The stem is green, highly suited for tender greens. Its greens become ready for picking 20–25 days after sowing, the yield being 130q/ha.
CO-3 (A.tritis): It is a selection from the local type and yields 30.72 tonnes of greens per hectare. It is a clipping type (A. tristis ). It lends itself for 10 clippings, commencing from 20 days after sowing and provides a continuous supply of luscious tender green for three months.
CO-4 (A. hypochondriacus): It is a green cum grain type from A. hypochondriacus L., which is suitable for growing in plains and hills throughout Tamil Nadu. It yields 2,555kg/ha of grain in addition 8,200 kg/ha of leaves on 25th day after thinning in a spacing of 30 x 30 cm. The crop duration is 90 days.
CO-5: The variety performs well during June-September and January-May. This variety has a leaf yield of 40 t/ha. The plants are medium in height with high biomass and nutritive value. The stem and petiole are pinkish red in color. The leaves are large obovate. It is also ideal for patio or container cultivation.
Lal Sag: This high yielding variety is grown quite popularly in many states of India. It produces seeds early but has small flowers. Besides, many other locally named varieties are also grown in different regions.
Pusa Kiran: Its leaves are glossy green with broad ovate lamina.The stem is glossy green. It is suitable for kharif. It becomes ready for first picking 21–25 days after sowing, the duration of harvest being 70–75 days. It takes 95–100 days to flower and yield is 35 tonnes/ha.
Pusa Lal Chaulai: It is suitable for kitchen gardening as well as for commercial cultivation in northern plains. Since the colour of stems and leaves is bright red (magenta), it is suitable for ornamental purpose also. The red dye extracted from its plants could be used as natural food-additive. The dye can also be used in textile or woollen industry for dyeing. Pusa Lal Chaulai is suitable for growing in both summer and rainy seasons. On an average, it yields 45–50 tonnes/ha.
Pusa Kirti: It is recommended for commercial cultivation in summer season. The leaves of Pusa Kirti are green with broad obvate lamina 6–8cm long and 4–5cm wide. Petiole is 3–4cm long. It is ready for first picking 30–35 days after sowing. Its subsequent cuttings may be taken at 10–12 days intervals, the yield being 50–55 tonnes/ha.
Sowing, seed rate and spacing
In North India amaranthus is sown from the middle of March up to the end of June, whereas in South India it is sown almost throughout tile year. The seed rate is about 2 kg/ ha for direct sowing and 1 kg for transplanted crop. Amaranthus seeds are very small, so they should be sown shallow, about 1.5 cm deep, mixed with fine soil or sand for even distribution. The seed is sown by broadcasting or by drilling in lines 20-23 cm apart, according to the variety and kind of the crop. In South India, there is also a practice of transplanting Chauli, especially with the variety Badi Chauli. Its seeds are sown in a small nursery and the young plants are later transplanted either as a pure crop or along the border of the beds of the other vegetables in rows 30 cm apart and 30 cm plant to plant distance. At the time of sowing there should be enough moisture in the field for proper germination otherwise a light irrigation, should be given after sowing.
Manures and Fertilizers
Amaranthus grows on the residual fertility of the previous crop grown in the field. However, the basal application of 25 tonnes of farmyard manure 50 kg of nitrogen, 50 kg of phosphorus 20kg of potash per hectare recommended as a basal application. For clipping type of amaranthus (CO3), a higher fertilizer dose of 75 kg of nitrogen, 25 kg/ha each of phosphorus and potash is recommended.
Since amaranth is first grown as a short duration crop, it requires plenty of water for growth and high yield. In summer, frequent irrigation is required at 4–6 days interval. Similarly in kharif, irrigation is scheduled as per the moisture content of the soil.
One or two weeding or hoeing is sufficient for controlling weeds. Hoeing between the rows not only check weeds but also reduces the number of irrigations.
The agro-techniques for seed production are normally similar to those for leaf production. For seed crop, the plants should be maintained at 30cm × 30cm spacing. The fertilizer schedule of 50kg each of N and P and 30kg K/ha is recommended for better seed yield.
Since it is a cross-pollinated crop, an isolation distance of about 400m is required between 2 cultivars. Generally, the crop used for leaf production is not used for seed production. Rogueing of off-types is highly essential at different stages of crop growth.
Harvesting of seeds starts when the plants turn yellow or deep brown in colour. Drying of inflorescence is practised while the sample seeds contain less than 15% moisture. Seeds are threshed with pliable bamboo sticks and strained through 2mm sieve. Dried seeds with 6% moisture content are stored after treating with Bavistin @ 2g/kg seed.
The general practise of harvesting amranthus is that the plants are pulled as a whole, washed and send to the market as a tender green. Cutting of amaranthus leaves start when plants are 25-30 cm tall. Only the fully grown side leaves are removed. The tops of the plants may also be cut leaving the lower leaves to produce new shoots in their axils. Picking is, subsequently done at weekly interval.
Storage and Marketing
The crop is taken to market immediately after harvesting. The weak, pale and disease affected leaves are discarded and healthy, succulent leaves are bundled into bunches for marketing.
These leaf bunches are put into wooden box and taken to the market. Amaranthus does not stand storage for more than few hours under ordinary conditions. Under cold storage conditions it can be stored for 10-15 days with 95% relative humidity.
Rohini,N.,1* , N. Pandiarana2
1Ph.D., Research Scholar, Department of Vegetable crops, HC &RI, TNAU- 641003
2 Ph.D., Research Scholar, BCKV, Kalyani, West Bengal-741235